Wire loop, semiconductor device having same and wire bonding method

ABSTRACT

A wire loop comprises a wire connecting a first bonding point and a second bonding point therethrough, wherein the wire includes a ball bonded to the first bonding point, a neck portion adjacent to the ball and a major portion extending from the neck portion to the second bonding point. The neck portion includes a riser part which extends, from the bonded ball, obliquely upward in a direction toward the second bonding point, and the riser part is formed by a top portion of the ball which has entered an opening of a capillary and been shaped at the time of ball bonding. The riser part is formed by inclining the top portion of the ball, which enters the opening of the capillary at the time of ball bonding, which inclining is done by moving the capillary obliquely upward toward the second bonding point.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wire bonding method for connecting afirst bonding point and a second bonding point through a wire, a wireloop having a certain shape and a semiconductor device having such awire loop incorporated therein.

2. Description of the Related Art

Conventionally, in a process of fabricating a semiconductor device, asshown in FIG. 9A or 9B, wire bonding for connecting a pad 2 a or a firstbonding point A of a semiconductor chip 2 attached to a lead frame 1 anda lead 1 a or a second bonding point Z of the lead frame 1 through awire 3 has been carried out. Typically, loop shapes of the wire 3connecting the first and second bonding points A and Z include atrapezoidal shape and a triangular shape shown in FIGS. 9A and 9B,respectively, as disclosed, for example, in U.S. Pat. No. 6,036,080 orJapanese Patent Application Laid-Open Publication No. 2000-277558.

The wire loop having a trapezoidal shape shown in FIG. 9A is formed by asequence of steps as shown in FIG. 10. First, in step (a) of FIG. 10, acapillary 4 through which the wire 3 passes is lowered and a ball 30which has been formed at a tip end of the wire 3 is bonded to the pad 2a of the chip 2 or first bonding point A. Then, in step (b) of FIG. 10,the capillary 4 is vertically raised to a point B while the wire 3 issupplied. Thereafter, in step (c) of FIG. 10, the capillary 4 ishorizontally moved to a point C in a direction opposite from the secondbonding point Z.

In general, such an operation of the capillary 4 to be moved in thedirection opposite from the second bonding point Z is referred to as a“reverse operation”. As a result, the portion of the wire 3 between thepoints A and C is formed to be inclined and the wire 3 is formed at anupper end of the inclined portion thereof with a bend 3 a by a lower endof the capillary 4. The portion of the wire 3 between the points A and Cthus supplied corresponds to the height of a neck portion H (or aportion of the wire 3 between the pad 2 a and the bend 3 a) and willconstitute the neck portion H.

Subsequently, in step (d) of FIG. 10, the capillary 4 is verticallyraised to a point D while the wire 3 is supplied. Then, in step (e) ofFIG. 10, the reverse operation of the capillary 4 is performed again,i.e. the capillary 4 is horizontally moved to a point E in the directionopposite from the second bonding point Z. As the result of this reverseoperation, the wire 3 has another inclined portion formed to beextending between the points C and E, and a bend 3 b is formed in anupper end of this inclined portion of the wire 3.

This inclined portion of the wire 3 thus supplied will constitute anupper base portion L (or a portion of the wire 3 between the bends 3 aand 3 b) of the wire loop having a trapezoidal shape shown in FIG. 9A.Thereafter, in step (f) of FIG. 10, the capillary 4 is vertically raisedto a point F so that the wire 3 is supplied by a length corresponding toa long inclined portion S (or a portion of the wire 3 between the bend 3b and the lead 1 a) of the wire loop shown in FIG. 9A. Subsequently, thecapillary 4 is lowered to the second bonding point Z via positions f₁and f₂, so that the wire 3 is bonded to the second bonding point Z orthe lead 1 a.

The wire loop having a triangular shape shown in FIG. 9B is formed by asequence of steps as shown in FIG. 11. Since the wire loop having atriangular shape is not provided with an upper base portion (L) unlikethe wire loop having a trapezoidal shape described above, in forming thewire loop of a triangular shape, the second reverse operation in steps(d) and (e) of FIG. 10 is not conducted. Therefore, in this instance, astep that corresponds to the steps (d), (e) and (f except for f₁ and f₂)of FIG. 10 is carried out only in step (d) of FIG. 11. Moreparticularly, steps (a), (b) and (c) of FIG. 11 are the same as thesteps (a), (b) and (c) of FIG. 10, and after the first reverse operationin step (c) of FIG. 11, the capillary 4 is vertically raised to a pointF in step (d) of FIG. 11 while the wire 3 is supplied. Subsequently, instep (e) of FIG. 11, the capillary 4 is moved via positions e₁ and e₂ ina manner similar to that in step (f) of FIG. 10, with the result thatthe wire 3 is bonded to the second bonding point Z or the lead 1 a.

However, in the above-described techniques, as the wire loop includesthe neck portion H having a somewhat large height, the wire loop becomeshigh and thus is rendered unstable. In addition, in a case where a wireloop is formed without any reverse operation of the capillary in orderto make the height of a neck portion H thereof small and the height ofthe neck portion H is reduced to a certain level or below, the neckportion H is liable to be damaged in drawing or moving the wire 3 toarrange it in place because of the wire 3 vertically extending from thefirst bonding point A.

Accordingly, various techniques have been proposed in order to solve theabove mentioned problems. For example, U.S. Patent ApplicationPublication No. 2004/0104477 or Japanese Patent Laid-Open PublicationNo. 2004-172477 discloses a wire loop connecting a first bonding pointand a second bonding point through a wire, wherein a top portion of aball bonded to the first bonding point, together with a part of thewire, is crushed.

The wire loop having such a shape can be formed as a wire loop having alow profile which is stable and strong in shape retention. Not only awire loop having a short wiring distance but also a wire loop having along wiring distance can be obtained as a stable wire loop having a lowprofile. In addition, the wire loop thus formed has a strong shaperetention which withstands a force or pressure exerted on the wire loopfrom outside. Therefore, the wire loop has an excellent shock absorbingfunction against a shock, such as a shock caused by contact of thecapillary or emission of an ultrasonic wave during bonding of the wireto the second bonding point, vibration of the wire, an external forcegenerated by flow of a molding material during injection of the moldingmaterial and the like, with the result that bending or tilting of thewire and a breakage in the neck portion of the wire loop can beeffectively prevented.

However, in the technique disclosed in U.S. Patent ApplicationPublication No. 2004/0104477, since part of the wire and the top of thebonded ball is crushed by the capillary at the first bonding point,there is a possibility that the first bonding point will be damaged. Inaddition, the wire which has been crushed at the first bonding point maybe caused to partly protrude in a direction opposite from the secondbonding point. In the case where wiring is finely effected and adirection of the wire loop is slanted with respect to an edge of asemiconductor chip, the protruding part of the wire may come intocontact with a wire of the adjacent first bonding point.

SUMMARY OF THE INVENTION

The present invention has been made in view of the foregoingdisadvantages of the prior art.

Accordingly, it is an object of the present invention to provide a wireloop having a low profile which is stable and of which a neck portion ishard to damage while no crushed part is formed by a capillary on a wireand a ball bonded to a first bonding point.

It is another object of the present invention to provide a semiconductordevice having said wire loop incorporated therein.

It is still another object of the present invention to provide a wirebonding method capable of forming said wire loop.

In accordance with one aspect of the present invention, a wire loop isprovided. The wire loop comprises: a wire connecting a first bondingpoint and a second bonding point therethrough; the wire including a ballbonded to the first bonding point, a neck portion adjacent to the balland a major portion extending from the neck portion to the secondbonding point; wherein the neck portion includes a riser part whichextends, from the bonded ball, obliquely upward in a direction towardthe second bonding point, and the riser part is formed by a top portionof the ball which has entered an opening of a capillary and been shapedat the time of ball bonding.

In a preferred embodiment of the present invention, the wire includes atleast one bend mark formed on the neck portion or the major portionthereof.

In a preferred embodiment of the present invention, the wire includes abend between the neck portion and the major portion; and a plurality ofthe bend marks are formed on the bend or in the vicinity of the bend.

In accordance with another aspect of the present invention, a wirebonding method for bonding a wire between a first bonding point and asecond bonding point using a capillary is provided. The wire bondingmethod comprises: bonding a ball formed on a tip end of the wire to thefirst bonding point; and inclining a riser part of the wire, whichextends from the bonded ball, toward the second bonding point, the riserpart being formed by a top portion of the ball which has entered anopening of the capillary and which has been shaped at the time of thebonding of the ball to the first bonding point.

In a preferred embodiment of the present invention, the wire bondingmethod further comprises forming at least one bend on a portion of thewire extending from the riser part thereof by moving the capillaryobliquely upward or by moving the capillary upward and then horizontallyor by moving the capillary upward and then obliquely downward.

In a preferred embodiment of the present invention, the inclining of theriser part is carried out by moving the capillary obliquely upward andincludes forming a bend on the riser part of the wire.

In accordance with still another aspect of the present invention, a wirebonding method for bonding a wire between a first bonding point and asecond bonding point using a capillary is provided. The wire bondingmethod comprises the steps of:

(a) bonding a ball formed on a tip end of the wire to the first bondingpoint;

(b) moving the capillary obliquely upward in a direction toward thesecond bonding point, to thereby make a first portion of the wire, whichhas entered an opening of the capillary at the time of the bonding ofthe ball to the first bonding point, extend obliquely upward in adirection toward the second bonding point;

(c) subsequently moving the capillary vertically and horizontally whilecarrying out loop control, to thereby form at least one bend on a secondportion of the wire extending from the first portion thereof; and

(d) thereafter, moving the capillary horizontally and vertically to thesecond bonding point while supplying the wire from the capillary andcarrying out loop control, and then bonding the wire to the secondbonding point.

In a preferred embodiment of the present invention, in the step (b),another bend is formed on the first portion of the wire.

In a preferred embodiment of the present invention, the step (c) iscarried out by moving the capillary obliquely upward or by moving thecapillary upward and then horizontally or by moving the capillary upwardand then obliquely downward.

In a preferred embodiment of the present invention, the step (c) isrepeatedly carried out to form a plurality of the bends on the secondportion of the wire.

In a preferred embodiment of the present invention, a resultant bend ofa large size is formed between the first portion and the second portionof the wire in the step (d), the at least one bend being disposed atsuch a position on the wire that the at least one bend will be situated,as a bend mark, on the resultant bend or in the vicinity of theresultant bend.

In accordance with a further aspect of the present invention, asemiconductor device is provided. The semiconductor device comprises: afirst bonding point; a second bonding point; and a wire bonded to thefirst bonding point and the second bonding point to connect the firstbonding point and the second bonding point therethrough, the wireincluding a ball bonded to the first bonding point, a neck portionadjacent to the ball and a major portion extending from the neck portionto the second bonding point; wherein the neck portion includes a riserpart which extends, from the bonded ball, obliquely upward in adirection toward the second bonding point, and the riser part is formedby a top portion of the ball which has entered an opening of a capillaryand been shaped at the time of ball bonding.

According to the present invention, the wire loop is provided on theneck portion thereof with the inclined riser part which is formed by atop portion of the ball which has entered an opening of a capillary andbeen shaped at the time of ball bonding, so that the wire loop has a lowprofile which is stable and which is formed without any damage caused toa neck portion thereof. In the preferred embodiment of the invention,the wire of the entire wire loop can be stably bent by forming aplurality of bends at desired locations of the wire by the capillarybeing moved obliquely upward or by the capillary being moved upward andthen horizontally or by the capillary being moved upward and thenobliquely downward.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and many of the attendant advantages of thepresent invention will be readily appreciated as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings; wherein:

FIG. 1A is an elevational view showing a shape of an embodiment of awire loop in a semiconductor device according to the present invention;

FIG. 1B is an enlarged fragmentary view showing the part encircled by atwo-dot chain line in FIG. 1A;

FIG. 2 is a schematic elevational view showing a moving path of acapillary to form the wire loop having a shape shown in FIGS. 1A and 1B;

FIG. 3 is an illustrative view showing a riser part being formed by atop portion of a ball which enters an opening of the capillary at thetime of ball bonding;

FIG. 4 is a schematic diagram showing wire shapes in respective steps inassociation with the movement of the capillary according to a method ofthe present invention by way of example;

FIG. 5A is a schematic diagram showing wire shapes in respective stepsin association with the movement of the capillary according to amodification of the method shown in FIG. 4;

FIG. 5B is a schematic elevational view showing a moving path of thecapillary to form the wire loop according to the steps of FIG. 5A;

FIG. 6A is a schematic diagram showing wire shapes in respective stepsin association with the movement of the capillary according to anothermodification of the method shown in FIG. 4;

FIG. 6B is a schematic elevational view showing a moving path of thecapillary to form the wire loop according to the steps of FIG. 6A;

FIG. 7A is an elevational view showing a shape of another embodiment ofa wire loop in a semiconductor device according to the presentinvention;

FIG. 7B is an enlarged fragmentary view showing the part encircled by atwo-dot chain line in FIG. 7A;

FIG. 8 is an elevational view showing a shape of still anotherembodiment of a wire loop in a semiconductor device according to thepresent invention;

FIGS. 9A and 9B are elevational views showing conventional wire loopshaving a trapezoidal shape and a triangular shape, respectively;

FIG. 10 is a schematic diagram showing wire shapes in respective stepsin association with the movement of the capillary to form the wire loopof a trapezoidal shape shown in FIG. 9A; and

FIG. 11 is a schematic diagram showing wire shapes in respective stepsin association with the movement of the capillary to form the wire loopof a triangular shape shown in FIG. 9B.

DETAILED DESCRIPTION OF THE INVENTION

Now, a wire loop, a semiconductor device and a wire bonding methodaccording to the present invention will be described hereinafter withreference to the accompanying drawings in which like parts in each ofthe several figures are identified by the same reference character ornumeral.

Referring first to FIGS. 1A and 1B, an embodiment of a wire loop and asemiconductor device 10 having the wire loop incorporated thereinaccording to the present invention is illustrated. In the semiconductordevice 10, a semiconductor chip 2 is attached to a lead frame 1 and isprovided thereon with a pad 2 a which is a first bonding point A. Thewire loop of a wire 3 is formed to have a substantially triangular shapein general and includes a neck portion H having a ball 30 bonded to thepad 2 a or first bonding point A and a major portion or generallyinclined portion S which has an end bonded to a lead 1 a of the leadframe 1 or a second bonding point Z. The neck portion H and the majorportion L are connected through a resultant bend 3A. Such constructionof the illustrated embodiment is approximately the same as that of aconventional semiconductor device. However, in the illustratedembodiment, the neck portion H includes a riser part h which extendsfrom the bonded ball 30 obliquely upward in a direction toward thesecond bonding point Z as shown in FIGS. 1A and 1B. The riser part h ofthe neck portion H is formed by a top portion of the ball 30 which hasentered an opening of a capillary 4 and which has been shaped at thetime of bonding the ball 30 onto the first bonding point A as shown inFIG. 3.

As the wire loop is provided in the neck portion H with the riser part hthus inclined toward the second bonding point Z, the neck portion H canbe formed to have a reduced height as compared to that of theconventional wire loop of a triangular shape shown in FIG. 9B withoutthe neck portion H being damaged. Therefore, the wire loop can be formedto have a low profile, leading to a reduction in thickness of thesemiconductor device 10.

Referring now to FIGS. 2 and 4, an embodiment of the wire bonding methodaccording to the present invention by which the semiconductor device 10shown in FIGS. 1A and 1B is obtained will be described. FIG. 2 shows amoving path P of a capillary 4 and a finished state of the wire loopconnected to the first and second bonding points A and Z by wirebonding.

First, in step (a) of FIG. 4, the capillary 4 is lowered while a clamp(not shown), which is used for clamping a wire 3 and releasing the same,is opened, so that a ball 30 formed on a tip end of the wire 3 is bondedto the first bonding point A. At this time, a top portion of the ball 30enters an opening of the capillary 4 and is deformed by the opening ofthe capillary 4. The thus deformed portion of the ball 30 forms a riserpart h of a neck portion H of the wire loop. Then, in step (b) of FIG.4, the capillary 4 is moved obliquely upward to a point B while the wire3 is supplied, so that the riser part h is inclined toward the secondbonding point Z and a bend 31 is formed in the riser part h. Thereafter,in step (c) of FIG. 4, the capillary 4 is vertically raised to a point Cwhich may be selected as desired while the wire 3 is supplied.

Subsequently, in step (d) of FIG. 4, the capillary 4 is horizontallymoved in a direction toward the second bonding point Z to a point C1. Asa result, a portion of the wire 3 between the bend 31 and the point C1is formed to be inclined and a bend 32 is formed at a top of thisportion of the wire 3. Then, in step (e) of FIG. 4, the capillary 4 isvertically raised to a point D which may be selected as desired whilethe wire 3 is further supplied.

Thereafter, in step (f) of FIG. 4, the capillary 4 is horizontally movedto a point D1 in a direction toward the second bonding point Z. As aresult, a portion of the wire 3 between the bend 32 and the point D1 isformed to be inclined and a bend 33 is formed at a top of this inclinedportion of the wire 3. Then, in step (g) of FIG. 4, the capillary 4 isvertically raised to a point E which may be selected as desired whilethe wire 3 is supplied.

Next, in step (h) of FIG. 4, a reverse operation of the capillary 4 iscarried out, i.e. the capillary 4 is substantially horizontally moved ina direction opposite from the second bonding point Z to a point F. Themovement of the capillary 4 from the point E to the point F forms a bend3B in the wire 3. Thereafter, in step (i) of FIG. 4, the capillary 4 isvertically raised to a point G which may be selected as desired whilethe wire 3 is delivered. Thus, the wire 3 having a length correspondingto the inclined major portion S of the wire loop shown in FIG. 2 hasbeen supplied from the capillary 4.

Subsequently, step (j) of FIG. 4 is conducted in the same manner as thatin the conventional method described above such that the capillary 4 islowered to be located at the second bonding point Z, resulting in thewire 3 being bonded to the second bonding point Z.

In step (h) of FIG. 4, the reverse operation of the capillary 4 isconducted to form the bend 3B in the wire 3. Instead, the capillary 4may be obliquely lowered to a point F1 as in step (h′) shown in FIG. 5A,to thereby form the bend 3B in the wire 3. Then, the capillary 4 ismoved in the same manner as in steps (i) and (j) of FIG. 4, resulting inthe wire loop being provided. In this case, the capillary 4 is movedalong a moving path P shown in FIG. 5B to form the wire loop.

In step (i) of FIG. 4, the capillary 4 is vertically raised to the pointG as described above. Instead, the capillary may be obliquely raised toa point G1 while supplying the wire 3 as in step (i′) shown in FIG. 6A,and then the capillary 4 is lowered to the second bonding point Z tobond the wire 3 thereto in the same way as in step (j) of FIG. 4. Inthis instance, the capillary 4 is moved along a moving path P shown inFIG. 6B to form the wire loop.

Incidentally, it is preferable that the capillary 4 be constructed to bemovable within a range of 0 to 500 μm and in directions over 360 degreesdefined on the basis of a line interconnecting the first bonding point Aand second bonding point Z. In addition, each of the bends 31, 32, 33and 3B may be formed by moving the capillary 4 obliquely upward or bymoving the capillary upward and then horizontally or by moving thecapillary 4 upward and then obliquely downward.

As described above, the obliquely upward movement of the capillary 4 instep (b) of FIG. 4 makes the riser part h adjacent to the top of thebonded ball 30 incline, whereby the wire loop having a low profile inwhich the neck portion H is kept at a reduced height can be provided. Inaddition, since a plurality of the bends 31, 32 and 33 are formed atlocations on the resultant bend 3A connecting the neck portion H and themajor portion S of the wire loop or in the vicinity of the resultantbend 3A, the wire loop of a low profile can be formed without causingany damage to the riser part h or the neck portion H as well as with nocrushed mark being left on the wire and/or the bonded ball at the firstbonding point A by the capillary 4. In the finished wire loop, the bends31, 32 and 33 are each left as a bend mark of a reduced dimension on thewire 3.

It has been found by the experiments that the height of the neck portionH needed to prevent damage to the neck portion H is 120 to 130 μm in theconventional wire loop of a triangular shape shown in FIG. 9B while theneeded height of the neck portion H is 65 to 70 μm in the wire loopaccording to the embodiment of the present invention described above.Incidentally, in the case of the wire loop in which a crushed mark orpart is formed on the wire and bonded ball at the first bonding point bythe capillary according to the technique shown in U.S. PatentApplication Publication No. 2004/0104477, it is possible for the heightof the neck portion to be rendered 50 μm or less.

In the embodiment described above, operations of forming the bends 31,32 and 33 are carried out three times in step (b), steps (c) to (d), andsteps (e) to (f) of FIG. 4, respectively. Such forming operations may berepeated a plurality of times less than or more than three times so asto form a plurality of bends at locations in the wire as desired. Forexample, as shown in FIGS. 7A and 7B, two of the bends 31 and 32 areformed in the wire 3 on the resultant bend 3A connecting the neckportion H and the major portion S or in the vicinity of the resultantbend 3A. In this case, the operations conducted in steps (c) and (d) ofFIG. 4 are omitted.

In this way, the wire is stably bent at a plurality of locations. As aresult, the riser part of the wire loop can be formed to have a strengthgreater than that of the conventional wire loop of a low profile, sothat the wire loop which is positionally stable and which has a strongshape retention can be formed.

The bend 3B formed on the inclined major portion S of the wire 3 isarranged so as to prevent the major portion S from upwardly expanding atthe time of bonding the wire 3 onto the second bonding point Z. In theembodiments described above, the major portion S of the wire 3 isprovided at an intermediate position thereof with only one bend 3B.However, a plurality of such bends may be provided at an intermediateposition or positions of the inclined major portion S of the wire 3and/or at a position near the second bonding point Z. In an embodimentof the wire loop shown in FIG. 8, two such bends 3B1 and 3B2 areprovided on the inclined major portion S of the wire 3.

As can been seen from the foregoing, in the wire bonding methodaccording to the present invention, the wire loop connecting the firstbonding point and the second bonding point therethrough is provided onthe neck portion thereof with the inclined riser part, to thereby reducethe height of the neck portion and provide the riser part with anincreased strength as compared to the conventional wire loop of a lowprofile. Such construction can provide a wire loop having a low profilewhich is stable and which is formed without any damage caused to a neckportion thereof.

While preferred embodiments of the invention have been described with acertain degree of particularly with reference to the drawings, obviousmodifications and variations are possible in light of the aboveteachings. It is therefore to be understood that within the scope of theappended claims, the invention may be practiced otherwise than asspecifically described.

1. A wire loop comprising: a wire connecting a first bonding point and asecond bonding point therethrough; said wire including a ball bonded tosaid first bonding point, a neck portion adjacent to said ball and amajor portion extending from said neck portion to said second bondingpoint; wherein said neck portion includes a riser part which extends,from the bonded ball, obliquely upward in a direction toward said secondbonding point, and said riser part is formed by a top portion of saidball which has entered an opening of a capillary and been shaped at thetime of ball bonding.
 2. The wire loop as defined in claim 1, whereinsaid wire includes at least one bend mark formed on said neck portion orsaid major portion thereof.
 3. The wire loop as defined in claim 2,wherein said wire includes a bend between said neck portion and saidmajor portion; and a plurality of the bend marks are formed on said bendor in the vicinity of said bend.
 4. A wire bonding method for bonding awire between a first bonding point and a second bonding point using acapillary, comprising: bonding a ball formed on a tip end of the wire tosaid first bonding point; and inclining a riser part of the wire, whichextends from the bonded ball, toward said second bonding point, saidriser part being formed by a top portion of the ball which has enteredan opening of said capillary and which has been shaped at the time ofthe bonding of said ball to said first bonding point.
 5. The wirebonding method as defined in claim 4, further comprising forming atleast one bend on a portion of the wire extending from said riser partthereof by moving said capillary obliquely upward or by moving saidcapillary upward and then horizontally or by moving said capillaryupward and then obliquely downward.
 6. The wire bonding method asdefined in claim 5, wherein the inclining of said riser part is carriedout by moving said capillary obliquely upward and includes forming abend on said riser part of the wire.
 7. A wire bonding method forbonding a wire between a first bonding point and a second bonding pointusing a capillary, comprising the steps of: (a) bonding a ball formed ona tip end of the wire to said first bonding point; (b) moving saidcapillary obliquely upward in a direction toward said second bondingpoint, to thereby make a first portion of the wire, which has entered anopening of said capillary at the time of the bonding of said ball tosaid first bonding point, extend obliquely upward in a direction towardsaid second bonding point; (c) subsequently moving said capillaryvertically and horizontally while carrying out loop control, to therebyform at least one bend on a second portion of the wire extending fromthe first portion thereof; and (d) thereafter, moving said capillaryhorizontally and vertically to said second bonding point while supplyingthe wire from said capillary and carrying out loop control, and thenbonding the wire to said second bonding point.
 8. The wire bondingmethod as defined in claim 7, wherein in the step (b), another bend isformed on said first portion of the wire.
 9. The wire bonding method asdefined in claim 7, wherein the step (c) is carried out by moving saidcapillary obliquely upward or by moving said capillary upward and thenhorizontally or by moving said capillary upward and then obliquelydownward.
 10. The wire bonding method as defined in claim 9, wherein thestep (c) is repeatedly carried out to form a plurality of the bends onsaid second portion of the wire.
 11. The wire bonding method as definedin claim 9, wherein a resultant bend of a large size is formed betweensaid first portion and said second portion of the wire in the step (d),said at least one bend being disposed at such a position on the wirethat said at least one bend will be situated, as a bend mark, on saidresultant bend or in the vicinity of said resultant bend.
 12. Asemiconductor device comprising: a first bonding point; a second bondingpoint; and a wire bonded to said first bonding point and said secondbonding point to connect said first bonding point and said secondbonding point therethrough, said wire including a ball bonded to saidfirst bonding point, a neck portion adjacent to said ball and a majorportion extending from said neck portion to said second bonding point;wherein said neck portion includes a riser part which extends, from thebonded ball, obliquely upward in a direction toward said second bondingpoint, and said riser part is formed by a top portion of the ball whichhas entered an opening of a capillary and been shaped at the time ofball bonding.
 13. The semiconductor device as defined in claim 12,wherein said wire includes at least one bend mark formed on said neckportion or said major portion thereof.
 14. The semiconductor device asdefined in claim 13, wherein said wire includes a bend between said neckportion and said major portion; and a plurality of the bend marks areformed on said bend or in the vicinity of said bend.